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Lindcott Armory

Rifle · SAAMI

.338 RCM

Also known as .338 Ruger Compact Magnum

Ruger and Hornady's compact .338 magnum — a beltless short-action cartridge delivering near-.338 Winchester Magnum ballistics.

Caliber
0.338″ · 8.585 mm
Introduced
2008
Case
Rebated
Parent
.375 Ruger
Primary use
Hunting
Status
Active

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VelocityBeing verified
EnergyBeing verified
Typical grains185 · 200 · 225 gr
Identity
Introduced
2008
Type
Rifle
Origin
United States
Inventor
Ruger / Hornady
Manufacturer
Hornady
Standard
SAAMI
Status
Active
Availability
Limited
Build
Case capacity
74 gr H₂O
Twist (typical)
1:10
Primer
Large Rifle
Case type
Rebated
Pressure & range
Max pressure
65,000 psi
Eff. range
350 yd
Max range
800 yd
Recoil
15–22 ft·lb

Introduced by Hornady

Ballistics

Published velocity/energy data isn't available for .338 RCM. Parent case: .375 Ruger.

Performance

Best for Withheld until verified
Best for Withheld until verified
Dimensionscase measurements · scale drawing · size vs familiar rounds

Case dimensions — the scale drawing at the top of the page is built from these.

SAAMI · verified
Measuremmin✓
Bullet ⌀ 8.590.338 ✓
Neck ⌀ 9.400.370 ✓
Shoulder ⌀ 13.080.515 ✓
Shoulder angle 30°— ✓
Base ⌀ 13.510.532 ✓
Rim ⌀ 13.510.532 ✓
Belt ⌀ n/a
Rim thickness 1.270.050 ✓
Neck length 8.140.320 ≈
Case length 51.182.015 ✓
Overall length 72.142.840 ✓

Size vs familiar rounds

Drawn at true 1:1 — every case is accurate relative to the others. Absolute size depends on your screen's pixel density, so measuring one against a real ruler may be off. .338 RCM is highlighted below.

Factory loads

Verification

Being verified

Advertised FPS, energy, and BC are withheld until loads clear verification.

Suitable powders

3 reloading powders listed for .338 RCM, fastest to slowest. Cross-reference in the finder →

Reloader 17Reloader 19IMR 4831
Reloading costestimate cost per round vs factory

Estimate your cost per round and how it compares to factory. Inputs are yours — nothing is stored.

Cost estimate only — not load data. Charge weight is your input; follow published manuals for safe charges.

Firearms chambered in .338 RCM

1 model in the database chamber .338 RCM. Browse all →

Ruger Hawkeye Alaskan

Lineage

Immediate parent
.375 Ruger
Family TreeOpen .338 RCM in the interactive cartridge family tree

Connected reference

Loads19 factory loads for .338 RCMReloading3 suitable powders — cross-referenceFirearmsFirearms in .338 RCM

History

Developed in 2008 by Ruger and Hornady for the Ruger Hawkeye compact bolt-action. The RCM used a rebated rim to fit a large case body on a standard magnum bolt face, achieving .338 Win Mag performance in a shorter, lighter rifle. Hornady produces factory ammunition in the Dangerous Game Series. The cartridge has found a following among Alaskan guides who prefer a lighter, more maneuverable rifle.

FAQs

What twist rate does .338 RCM use?
.338 RCM typically uses a 1:10 twist rate.
What bullet diameter is .338 RCM?
.338 RCM uses a 0.338″ (8.585 mm) diameter bullet.
Is .338 RCM still in production?
.338 RCM is active; typical availability is limited.
What is .338 RCM used for?
.338 RCM is primarily used for hunting.
What is .338 RCM based on?
.338 RCM is derived from the .375 Ruger case.
What are the best powders for .338 RCM?
Reloading powders commonly listed for .338 RCM include Reloader 17, Reloader 19, IMR 4831.

Sources & provenance

Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 19 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →